1. Field of the Invention
The present invention relates to a method for displaying an image by using a ferroelectric material. In addition, the present invention relates to an apparatus for executing the above method. Further, the present invention relates to an image display medium which is used in the method.
2. Description of the Related Art
The liquid crystal display apparatus is one of the currently known image display apparatuses. In most of the liquid crystal display apparatuses currently used, a display signal applied to each pixel is updated at a predetermined frame frequency, e.g., 60 Hz. When an image display apparatus is driven in this manner, a voltage is required to be continuously applied to each pixel even when a still image is displayed. Therefore, the above manner of driving an image display apparatus is disadvantageous for reduction of energy consumption.
In order to solve the above problem, a liquid crystal display apparatus having an image holding function has been proposed, for example, by Japanese patent application, No. 6(1994)-312357 corresponding to Japanese Unexamined Patent Publication No. 8(1996)-146457. In this liquid crystal display apparatus, a ferroelectric material is series-connected to a pixel electrode which applies a voltage to a portion of a liquid crystal layer corresponding to each pixel, and the voltage is applied to the portion of the liquid crystal layer by the action of polarization charges, which are generated by applying a voltage to the ferroelectric material so as to cause polarization inversion. Since the state of the polarization inversion is maintained in the above construction, a desired voltage can be continuously applied to each portion of the liquid crystal layer corresponding to each pixel. Thus, a liquid crystal display apparatus having an image holding function is realized.
However, in the above liquid crystal display apparatus, an image is basically displayed by using a liquid crystal panel, which is expensive. Further, an expensive electric circuit is necessary for controlling the voltage application to the liquid crystal panel for each pixel. Therefore, manufacturing cost is high.